6 Simple ways to speed up your react native app. – codeburst

6 Simple ways to speed up your #reactnative app.  #redux

  • shouldComponentUpdate life-cycle method is used in regular non pure React Component to cancel the re-render by returning false in certain scenarios.Following two code samples do the same thing.class MyComponent extends React.PureComponent { //}class MyComponent extends React.Component { // nextState) { if(this.props.firstProp === nextProps.
  • firstProp this.props.secondProp === nextProps.secondProp) { return false; } return true } //}Both of the above examples can help you save some wasted renders.
  • Having a unique key on every list item, saves react re-rendering it again.class MyComponent extends React.PureComponent { render() { return this.props.data.map((item, i) = { return Text key={item.id}{item.title}/Text }); }}3.
  • Bind early and don’t create functions inside render.Do thisclass MyComponent extends React.PureComponent { constructor(props) { super(props); this.doWork = this.doWork.bind(this); } doWork() { // doing some work here.
  • // this.props.dispatch…. } render() { return Text onPress={this.doWork}Do Some Work/Text } }Don’t do this inside render.Text onPress={ () = this.doWork() }Do Some Work/TextorText onPress={ this.doWork.bind(this) }Do Some Work/TextBecause render is called very often and every time you do any of the two things above, a new function is created.4.

In my previous article I have talked about hacking event loop for improving performance of your app. Your goal is to retain 60 FPS throughout. All of that applies to react or react native app as well…
Continue reading “6 Simple ways to speed up your react native app. – codeburst”

Impress Your Friends With Code Splitting in React – Hacker Noon

Impress Your Friends With #Code Splitting in #ReactJS:  by @burkeholland #JavaScript

  • Both of those actions show the edit form.First I am going to add a spot in my state for this “EditForm” component to live.class Heroes extends Component { constructor(props) { super(props); this.state = { …, lazyEditHero: null } } …, render() { return ( … ) }}I put mine in…
  • I have put this in a function called LoadEditFormclass Heroes extends Component { constructor(props) { super(props); this.state = { … lazyEditHero: null } } async LoadEditForm() { const { default : EditHero } = await import(‘.
  • /EditHero’); this.setState({ lazyEditHero: EditHero }) } render() { return ( … ) }}Now we just need to call this LoadEditForm from the two functions that trigger the editor component to be shown.class Heroes extends Component { constructor(props) { super(props); this.state = { … lazyEditHero: null } } async LoadEditForm() {…
  • /EditHero’); this.setState({ lazyEditHero: EditHero }) } handleSelect = async hero = { await this.LoadEditForm(); this.setState({ selectedHero: hero }); } handleEnableAddMode = async () = { await this.LoadEditForm(); this.setState({ addingHero: true, selectedHero: { id: ”, name: ”, saying: ” } }); } … render() { return ( … ) }}A few…
  • This also allows us to pass any props to our component when it is so lazily loaded.class Heroes extends Component { constructor(props) { super(props); this.state = { … lazyEditHero: null } } async LoadEditForm() { const { default : EditHero } = await import(‘.

In preparation for the DevUp keynote a few weeks ago, I took some time to learn the minimum amount possible to demonstrate code splitting in React. Now your first reaction is probably… As part of the…
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7 Strengths of #ReactJS Every Programmer Should Know About

7 Strengths of #ReactJS Every Programmer Should Know About

  • React is blazingly fastIt is actually much faster than manually manipulating the DOM, which is the reason why Flipboard has built their own React-Canvas library to achieve 60fps performance on the mobile web.Modifying the DOM after every change can be slow, therefore React creates a simplified JavaScript version of DOM called VirtualDOM and uses a diffing algorithm to apply only necessary changes to the real DOM.JavaScript is a reasonably fast language, and typical web apps consist of only several hundreds of DOM elements.
  • They have invested years into creating the Facebook site, so a complete rewrite just to use React would not be justifiable.It is really easy to use React with jQuery, Angular, Backbone, or any other JavaScript framework.4.
  • You can create truly native apps with JavaScript and other tools you know from the web.
  • Some of the biggest innovations in React were actually inspired by ClojureScript, some were taken from Ember, and some come from Elm.Whether it is ClojureScript, Elm, Angular, or Ember, these great people are part of our Reactive Community, and they remind us why we should work together every day.The React ecosystem is extremely focused on developer experience and productivity.
  • But Facebook is not the only big supporter of the React community: Yahoo, Mozilla, Airbnb, Netflix, and other big companies use React in production and have supported the community with useful open-source libraries and tools.6.

In the past six years, we have seen a huge rise of JavaScript on the web. It has become a prominent server-side language and a popular compile target for other languages. Offline-first SPAs have…
Continue reading “7 Strengths of #ReactJS Every Programmer Should Know About”

7 Strengths of #ReactJS Every Programmer Should Know About

7 Strengths of #ReactJS Every Programmer Should Know About:  #JavaScript

  • React is blazingly fastIt is actually much faster than manually manipulating the DOM, which is the reason why Flipboard has built their own React-Canvas library to achieve 60fps performance on the mobile web.Modifying the DOM after every change can be slow, therefore React creates a simplified JavaScript version of DOM called VirtualDOM and uses a diffing algorithm to apply only necessary changes to the real DOM.JavaScript is a reasonably fast language, and typical web apps consist of only several hundreds of DOM elements.
  • They have invested years into creating the Facebook site, so a complete rewrite just to use React would not be justifiable.It is really easy to use React with jQuery, Angular, Backbone, or any other JavaScript framework.4.
  • You can create truly native apps with JavaScript and other tools you know from the web.
  • Some of the biggest innovations in React were actually inspired by ClojureScript, some were taken from Ember, and some come from Elm.Whether it is ClojureScript, Elm, Angular, or Ember, these great people are part of our Reactive Community, and they remind us why we should work together every day.The React ecosystem is extremely focused on developer experience and productivity.
  • But Facebook is not the only big supporter of the React community: Yahoo, Mozilla, Airbnb, Netflix, and other big companies use React in production and have supported the community with useful open-source libraries and tools.6.

In the past six years, we have seen a huge rise of JavaScript on the web. It has become a prominent server-side language and a popular compile target for other languages. Offline-first SPAs have…
Continue reading “7 Strengths of #ReactJS Every Programmer Should Know About”

7 Strengths of #ReactJS Every Programmer Should Know About

7 strengths of #ReactJS every programmer should know about ►►►  #JavaScript

  • React is blazingly fastIt is actually much faster than manually manipulating the DOM, which is the reason why Flipboard has built their own React-Canvas library to achieve 60fps performance on the mobile web.Modifying the DOM after every change can be slow, therefore React creates a simplified JavaScript version of DOM called VirtualDOM and uses a diffing algorithm to apply only necessary changes to the real DOM.JavaScript is a reasonably fast language, and typical web apps consist of only several hundreds of DOM elements.
  • They have invested years into creating the Facebook site, so a complete rewrite just to use React would not be justifiable.It is really easy to use React with jQuery, Angular, Backbone, or any other JavaScript framework.4.
  • You can create truly native apps with JavaScript and other tools you know from the web.
  • Some of the biggest innovations in React were actually inspired by ClojureScript, some were taken from Ember, and some come from Elm.Whether it is ClojureScript, Elm, Angular, or Ember, these great people are part of our Reactive Community, and they remind us why we should work together every day.The React ecosystem is extremely focused on developer experience and productivity.
  • But Facebook is not the only big supporter of the React community: Yahoo, Mozilla, Airbnb, Netflix, and other big companies use React in production and have supported the community with useful open-source libraries and tools.6.

In the past six years, we have seen a huge rise of JavaScript on the web. It has become a prominent server-side language and a popular compile target for other languages. Offline-first SPAs have…
Continue reading “7 Strengths of #ReactJS Every Programmer Should Know About”

Redux with React

Redux with React - First Look  #reactjs #Redux #javascript #appdev #programming #devops

  • Let’s start with the basics:

    According to the official site Redux is defined as a predictable state container for JavaScript apps.

  • In Redux, reducers are functions (pure, I will explain what a pure function is later) that take the current state of the application and an action and then return a new state.
  • 3 – Store

    Store is the object that holds the application state and provides a few helper methods to access the state, dispatch actions and register listeners.

  • – Changes are made with pure functions: To specify how the state tree is transformed by actions, you write pure reducers.
  • You might be interested in:

    Predictability of outcome:

    There is always one source of truth, the store, with no confusion about how to sync the current state with actions and other parts of the application.

influenced by Flux architecture and became popular very quickly, excellent documentation and size (2 KB). Also it is very easy to use redux with react
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Testing Common Redux Patterns in React Using AVA

Testing common #Redux patterns in #ReactJS using AVA:

  • Let’s configure the Redux store using our root reducer.
  • As the second argument, we are passing the action which toggles the state of the todo with the given id .
  • When dispatched, the action will cause a todo item of a given id to switch its state, for instance from completed to not completed.
  • /actions’ ; const store = configureStore ({ todos : [ { id : 0 , completed : false , text : ‘buy milk’ }, { id : 1 , completed : false , text : ‘walk the dog’ }, { id : 2 , completed : false , text : ‘study’ } ] }); store .
  • Reducers react to dispatched actions by modifying the store.

This is the second tutorial in our series on testing React and Redux applications.
If you haven’t read the first part, we encourage you to do so.
Continue reading “Testing Common Redux Patterns in React Using AVA”